Flexible block brush



FIG. 1 is a perspective view of a flexible block brush showing my new design;

FIG. 2 is an elevational view of one side thereof, the opposite side being a mirror image;

FIG. 3 is an elevational view of one end thereof, the opposite end being a mirror image;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a flexible block brush, as shown and described. 